October in Irkutsk averages a daily high of 7.8°C with nights around -2.4°C. Expect roughly 8.1 wet days totalling 21.1mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Irkutsk is May–August.
Based on IRKUTSK, RS (5.2km), 1995–2024. 24 years of October data.